Interpretive Summary: Managing forages as living mulches during row crop production requires suppressing the forages to produce economical crop yields. The objective of this research was to identify forage plants with varied growth habit, persistence, and yield potential to provide desirable ecosystem functions and high forage yields in a multifunctional cropping system. Alfalfa, kura clover, and birdsfoot trefoil were evaluated in simple and binary mixtures and reed canarygrass and orchardgrass were included in three-way mixtures in a corn-soybean-forage rotation. The forages were managed as perennial cover crops in corn and soybean and suppressed using a 10 inch glyphosate band over the row and harvested four times during the forage year. In the forage year, treatments containing alfalfa produced the highest yields. Three-way mixtures provided greater weed suppression in the interrow than simple or binary mixtures. Kura clover provided greater weed suppression than alfalfa in the interrow and birdsfoot trefoil did not persist. Reed canarygrass exhibited better stability than orchardgrass. Consequently, the best combination of species to use as living mulches during row crop production and to provide high forage yields and lower weed densities during the forage phase in this crop rotation includes alfalfa, kura clover, and reed canarygrass. Seeding an unadapted alfalfa in the spring of the forage year will supplement yield and suppress weeds in the former crop row. Farmers using this type of system can diversify their cropping systems by adding a forage year in the corn-soybean rotation and obtain high forage yields and eliminate the lower yields usually obtained during a perennial forage establishment year.

Technical Abstract:
Managing forages as living mulches during row crop production requires suppressing the forages to produce economical crop yields. The objective of this research was to identify forage plants with varied growth habit, persistence, and yield potential to provide desirable ecosystem functions and high forage yields in a multifunctional cropping system. Alfalfa (Medicago sativa L.), kura clover (Trifolium ambiguum Bieb.), and birdsfoot trefoil (Lotus corniculatus L.) were evaluated in simple and binary mixtures and reed canarygrass (Phalaris arundinacea L.) and orchardgrass (Dactylis glomerata L.) were included in three-way mixtures in a corn (Zea mays L.)-soybean [Glycine max (L.) Merr.]-forage rotation with all phases present each year. The forages were managed as perennial cover crops in corn and soybean and suppressed using a 25 cm glyphosate band over the row and harvested four times during the forage year. In the forage year, treatments containing alfalfa produced the highest yields (7,824 kg ha-1 average dry matter 2005-2007). Three-way mixtures provided greater weed suppression in the interrow than simple or binary mixtures in 2 of 3 yr (80 vs 127 weeds m-2, 2005-2006 average). Kura clover provided greater weed suppression than alfalfa in the former row (108 vs 186 weeds m-2) and birdsfoot trefoil did not persist. Reed canarygrass exhibited better stability in sward composition (20% in 2005 and 22% in 2007) than orchardgrass (58% in 2005 and 16% in 2007). Consequently, the best combination of species to use as living mulches during row crop production and to provide high forage yields and lower weed densities during the forage phase in this crop rotation includes alfalfa, kura clover, and reed canarygrass. Seeding an unadapted alfalfa in the spring of the forage year will supplement yield and suppress weeds in the former crop row.